Tobacco and alcohol often are used simultaneously by young adults, and their co-use is associated with greater likelihood of a dependence diagnosis in adulthood, disease, and eventual death from both substances. With wide reach and engagement among users, social media offer phenomenal opportunities to engage young people in an intervention for tobacco use and heavy drinking, and to foster socially supportive communities in which individuals can help each other reduce risky behaviors and maintain these changes over time. Preliminary work by our group has shown that young adults have an interest in using Facebook to quit smoking and that an intervention tailored to readiness to quit would be well received. Funded with a career development award from NIDA, the Principal Investigator has developed the Facebook Tobacco Status Project (TSP), a motivationally-tailored smoking cessation intervention for young adults based on US Clinical Practice Guidelines, and we have strong preliminary results. The present study seeks to determine whether adding an alcohol component (TSP +ALC) can lead to improved individual or combined tobacco and heavy episodic drinking (HED) outcomes among young adults who engage in both health risk behaviors. Phase I will develop TSP+ALC based on focus groups with young adults who smoke and have HED (5+ drinks for men, 4+ for women), the existing TSP, US Clinical Practice Guidelines for smoking cessation, and National Institute on Alcohol Abuse and Alcoholism (NIAAA) guidelines for changing alcohol use. We will then use Facebook to recruit and conduct usability testing with 30 young adults who use tobacco and alcohol and revise the intervention according to feedback received. Phase II will evaluate, in a pilot randomized trial, the feasibilit and initial efficacy of TSP+ALC compared to TSP, with 160 US young adults recruited online. Young adults who smoke and have HED will be randomized to receive TSP or TSP+ALC. Both interventions will assign participants to a private Facebook group tailored to their readiness to quit tobacco and deliver a 90 day intervention including Facebook postings and weekly The Dr. Is In sessions with a trained counselor to guide group sessions. All participants will be offered 2-week introductory supply of nicotine patch. Participants will complete baseline, 3, 6, and 12 months follow-up assessments online. The primary outcome will be biochemically-verified 7-day point prevalence abstinence at each timepoint. Secondary outcomes include days of HED, dependence symptoms, readiness to quit, and thoughts about abstinence for smoking and HED. Facebook data will determine patterns of engagement, types of posts that attract the most and quickest user activities, and the relationship between user activity and tobacco use and HED in each group. Results will be used to design a randomized clinical trial powered to detect significant effects across groups. This line of research will inform new digital substance use interventions for young adults with great potential for cost-effectiveness and widespread dissemination.